Fix phpstan/phpstan#9844: Calling a static method over non-generic class-string results in ErrorType

src/Analyser/ExprHandler/MethodCallHandler.php

@@ -288,27 +288,35 @@
 	{
 		if ($expr->name instanceof Identifier) {
 			if ($scope->nativeTypesPromoted) {
+				$nativeType = $scope->getNativeType($expr->var);
 				$methodReflection = $scope->getMethodReflection(
-					$scope->getNativeType($expr->var),
+					$nativeType,
 					$expr->name->name,
 				);
 				if ($methodReflection === null) {
-					$returnType = new ErrorType();
+					$nativeObjectType = $nativeType->getObjectTypeOrClassStringObjectType();
+					$returnType = $nativeObjectType->isObject()->yes() && $nativeObjectType->getObjectClassNames() === []
+						? new MixedType()
+						: new ErrorType();
 				} else {
 					$returnType = ParametersAcceptorSelector::combineAcceptors($methodReflection->getVariants())->getNativeReturnType();
 				}
 
 				return NullsafeShortCircuitingHelper::getType($scope, $expr->var, $returnType);
 			}
 
+			$calledOnType = $scope->getType($expr->var);
 			$returnType = $this->methodCallReturnTypeHelper->methodCallReturnType(
 				$scope,
-				$scope->getType($expr->var),
+				$calledOnType,
 				$expr->name->name,
 				$expr,
 			);
 			if ($returnType === null) {
-				$returnType = new ErrorType();
+				$objectType = $calledOnType->getObjectTypeOrClassStringObjectType();
+				$returnType = $objectType->isObject()->yes() && $objectType->getObjectClassNames() === []
+					? new MixedType()
+					: new ErrorType();
 			}
 			return NullsafeShortCircuitingHelper::getType($scope, $expr->var, $returnType);
 		}

src/Analyser/ExprHandler/StaticCallHandler.php

@@ -335,14 +335,17 @@
 				$staticMethodCalledOnType = TypeCombinator::removeNull($scope->getType($expr->class))->getObjectTypeOrClassStringObjectType();
 			}
 
+			$methodName = $expr->name->toString();
 			$callType = $this->methodCallReturnTypeHelper->methodCallReturnType(
 				$scope,
 				$staticMethodCalledOnType,
-				$expr->name->toString(),
+				$methodName,
 				$expr,
 			);
 			if ($callType === null) {
-				$callType = new ErrorType();
+				$callType = $staticMethodCalledOnType->isObject()->yes() && $staticMethodCalledOnType->getObjectClassNames() === []
+					? new MixedType()
+					: new ErrorType();
 			}
 
 			if ($expr->class instanceof Expr) {

tests/PHPStan/Analyser/nsrt/bug-9844.php

@@ -0,0 +1,22 @@
+<?php declare(strict_types = 1);
+
+namespace Bug9844;
+
+use function PHPStan\Testing\assertType;
+
+class HelloWorld
+{
+
+	/**
+	 * @param class-string $class
+	 */
+	public function sayHello(string $class, string $method, string $property): void
+	{
+		assertType('mixed', $class::foo());
+		assertType('mixed', $class->foo());
+		assertType('mixed', $class?->foo());
+		assertType('mixed', $class::$method());
+		assertType('mixed', $class->$property);
+		assertType('mixed', $class?->$property);
+	}
+}